Ethylene polymers such as high density polyethylene (HDPE) homopolymer or copolymer and linear low density polyethylene (LLDPE) copolymer can be produced using various combinations of catalyst systems and polymerization processes. Ziegler-Nana, metallocene, and chromium-based catalyst systems are the most common catalyst systems used to produce such ethylene polymers.
However, regardless of the catalyst system, ethylene polymers that contain a phenolic antioxidant can exhibit color formation, such as yellowing, over time or when subjected to high temperatures. It would be beneficial to have an improved polymer stabilization system that provides long-term color stability to the ethylene polymer. Accordingly, it is to these ends that the present invention is generally directed.